The South China block-Indochina collision: Where, when, and how?

http://repository.vnu.edu.vn/handle/VNU_123/32616

This study uses new field observations and existing studies to shed new light on the origin and significance of two NW-SE striking orogens in NW and NE Vietnam. 



We conclude that the architecture of each belt is a stack of NE-directed nappes formed either under deep ductile synmetamorphic conditions, or under shallow depth in the SW and NE parts, respectively. 
The Song Ma zone and Song Chay ophiolitic melange represent two ophiolitic sutures. 
However, the Late Permian Song Da and Babu mafic rocks are not ophiolites but intraplate basalts related to the Emeishan plume. 
A Late Triassic unconformity, the 225-205. Ma postorogenic plutonism, and the 250-230. Ma syntectonic metamorphism support an Early to Middle Triassic age for these tectonic events. 
Both NW and NE belts are due to SW-directed subduction with arc magmatism, ocean closure, and continental collision. 
Though two contemporary S-dipping subduction zones might explain the structural evolution of the two belts, a single convergent system, offset by the Tertiary Red River fault, is preferred as this S-directed subduction better accounts for the Late Permian intraplate magmatism. 
This scenario is discussed in the general geodynamic framework of SE Asia


Title: The South China block-Indochina collision: Where, when, and how?
Authors: Faure, Michel
Lepvrier, Claude
Van, Nguyen Vuong
Van, Tich Vu
Lin, Wei
Chen, Zechao
Keywords: Asia paleogeodynamics
Collision orogen
Indochina
South China block
Triassic (Indosinian) orogeny
Issue Date: 2014
Publisher: Journal of Asian Earth Sciences
Citation: Scopus
Abstract: This study uses new field observations and existing studies to shed new light on the origin and significance of two NW-SE striking orogens in NW and NE Vietnam. We conclude that the architecture of each belt is a stack of NE-directed nappes formed either under deep ductile synmetamorphic conditions, or under shallow depth in the SW and NE parts, respectively. The Song Ma zone and Song Chay ophiolitic melange represent two ophiolitic sutures. However, the Late Permian Song Da and Babu mafic rocks are not ophiolites but intraplate basalts related to the Emeishan plume. A Late Triassic unconformity, the 225-205. Ma postorogenic plutonism, and the 250-230. Ma syntectonic metamorphism support an Early to Middle Triassic age for these tectonic events. Both NW and NE belts are due to SW-directed subduction with arc magmatism, ocean closure, and continental collision. Though two contemporary S-dipping subduction zones might explain the structural evolution of the two belts, a single convergent system, offset by the Tertiary Red River fault, is preferred as this S-directed subduction better accounts for the Late Permian intraplate magmatism. This scenario is discussed in the general geodynamic framework of SE Asia
Description: Journal of Asian Earth Sciences, Volume 79, Issue PA, 5 January 2014, Pages 260-274
Journal of Asian Earth Sciences
URI: http://www.sciencedirect.com/science/article/pii/S1367912013004987
http://repository.vnu.edu.vn/handle/VNU_123/32616
ISSN: 13679120
Appears in Collections:Bài báo của ĐHQGHN trong Scopus

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